Thursday, I began compiling a list of things I've learned from watching all 15 spring practices. I talked about the thin linebacking corps, the depth of the rest of the team and the freakishly athletic Taylor Mays.

Notice I didn't mention quarterbacks once.

That's about to change.

Lesson Four:You can never talk about quarterbacks too much.

Trust me, I tried to refrain myself from writing about the quarterbacks exclusively each day, but it was just impossible.

When the last four quarterbacks to start at USC have found their way to the NFL, three as first-round selections, there's going to be a ton of attention paid to the battle for the next starter.

Still, I had no idea.

Readers devoured things like rep-by-rep breakdowns and USCfootball.com's innovative QBR. Still, over the course of the spring, it did get tiring - until a few things happened.

Aaron Corp's interception streak became a topic of daily conversation, ending coincidentally two practices after being named the starter. Add that with the emergence of Matt Barkley throughout camp and the descent down the depth chart of Mitch Mustain, and the battle finally started to pick up extra steam.

The good news is that this is far from over.

Lesson Five:Barkley's wise beyond his years.

I can't stress enough how old Barkley seems when he's around the practice field. He never looks like a wide-eyed buck. He seems like he's been in this position before even though he's never been on a stage quite this big.

He handles the fans marvelously. He's signing autographs and posing for picture like someone who has been doing for years.

Certainly earning the starting spot at Mater Dei as a freshman helped get Barkley ready for all the pressure and the hype that came with being a top-ranked recruit for years. But as a collegiate player, it would've been understandable if it took time for him to blossom.

It didn't.

Barkley's handling of all the hype and expectations and extra attention might be the biggest accomplishment of the spring.

Lesson Six:Jeremy Bates will have the offense looking differently, for better or for worse.

When there's a new playcaller in place, obvious the offense is going to undergo a change, and from what I saw this spring, there are some noticeable differences.

Bates wants to get the ball to the running backs in ways other than handing it off. Over the course of the spring, the USC quarterbacks ran a lot of screen plays - something that didn't happen much in 2008.

Bates also isn't afraid to call a draw play in third-and-long situations, a very NFL play call.

He's also been called a more aggressive playcaller by Pete Carroll and the quarterbacks, even though it didn't always seem like it. I think once the season rolls around, Bates will continue to get the playmakers involved without asking too much of the USC quarterback.